1. Field of the Invention
The present invention generally relates to a package, and more particularly to a semiconductor package, wherein an active type heat-spreading element is not covered by a passive type heat-spreading element, whereby the heat of the chip can be directly conveyed to the environment located outside the semiconductor package via the active type heat-spreading element, and the weight of the passive type heat-spreading element cannot be transferred to the chip so as to decrease the pressure of the chip.
2. Description of the Related Art
As lighter and more complex electronic devices are required gradually, the processing speed and complexity of a chip is becoming more and more high. It is necessary that a semiconductor chip provides more leads for inputting and outputting signals. A ball grid array (BGA) package is a package which is widely used and has quantities of leads. Furthermore, as the density of elements on the semiconductor chip is increased, the heat resulted therefrom is increased gradually. Thus, there is another important problem how to effectively dissipate the heat resulted from the semiconductor chip.
Referring to FIG. 1, it depicts a conventional ball grid array (BGA) flip chip package 10. The package 10 includes a chip 30, a substrate 40, a heat spreader 12 and a stiffener 20. The chip 30 has an active surface 32, a back surface 34 and a plurality of bumps 36 disposed on the active surface 32. The substrate 40 is adapted to support the chip 30 and has a plurality of traces (not shown) electrically connected to the bumps 36 of the chip 30. The stiffener 20 is attached on the upper surface 26 of the substrate 40 by a first adhesive 42. The heat spreader 12 is attached on the stiffener 20 by a second adhesive 44. A thermally conductive material (TIM) 46 is disposed between the back surface 34 of the chip 30 and the heat spreader 10 for helpfully dissipating the heat resulted from the chip 30 during operation. A plurality of solder balls 22 are disposed on the lower surface 24 of the substrate 40.
However, this heat spreader 12 is a passive type heat-spreading element rather than an active type heat-spreading element. In other words, the heat spreader 12 dissipates the heat naturally and passively, but dose not dissipate the heat forcedly and actively by inputting the energy. Although the active type heat-spreading element needs to input the energy, the efficiency of heat dissipation of the active type heat-spreading element is higher than that of the passive type heat-spreading element.
Taiwan Patent Application Number 093138692 is filed on Dec. 14, 2004 (the application date). The applicant of this Taiwan patent application is same as that of the present application: Advanced Semiconductor Engineering, Inc. Referring to FIG. 2, this Taiwan patent application discloses a semiconductor package 100 including a carrier 110, a chip 120 and a thermoelectric cooler (TEC) 130. The chip 120 is disposed on the carrier 110 and electrically connected to the carrier 110 by bumps 180. The TEC 130 is disposed on the chip 120 and electrically connected to the carrier 110 by bumps 190. The semiconductor package 100 further includes an encapsulant 140 for mounting the chip 120 and the TEC 130 on the carrier 110. A plurality of solder balls 160 are disposed on the carrier 110.
The TEC 130 has first and second surfaces 132, 134. The temperature of the first surface 132 can be lower than that of the second surface 134 when the TEC 130 is energized. In other words, when the energy is inputted to the TEC 130, the first surface 132 is a surface which has a low temperature and absorbs the heat, and the second surface 134 is a surface which has a high temperature and dissipates the heat. The first surface 132 of the TEC 130 contacts the chip 120, and thus the TEC 130 can convey the heat generated by the chip 120 from the first surface 132 to the second surface 134 so as to achieve an objective of fast dissipating heat. The semiconductor package 100 further includes a passive type heat-spreading element 150, which covers and contacts the TEC 130 for conveying the heat of the second surface 134 of the TEC 130 to an environment located outside the semiconductor package 100.
However, the TEC 130 is covered by the passive type heat-spreading element 150, and thus the heat of the second surface 134 of the TEC 130 cannot be directly conveyed to the environment located outside the semiconductor package 100. In fact, the heat of the second surface 134 of the TEC 130 is indirectly conveyed to the environment located outside the semiconductor package 100 via the passive type heat-spreading element 150. Furthermore, the weight of the passive type heat-spreading element 150 presses on the chip 120 so as to increase the pressure of the chip 120.
Accordingly, there exists a need for a semiconductor package capable of solving the above-mentioned problems.